Hey,

So for the last month and a half I have been battling some unknown electrical problem. Battery shows 12.6v in link when ignition is switched on, alternator relay has been changed, 3 remanufactured (advance) alternators have been on the car and last night I swapped to a Saturn alternator. All of them would show proper voltage on the first start-up after install and I'd be happy. The second time I would start the car the voltage would be lower and then gradually drop down to the bottom of the boost gauge (I have it set to be my "impending stall" or battery gauge). By the third time I start the car the voltage just drops like it is not charging at all and the car will shut off if I do not keep the revs up. The car will start right back up afterwards. The only thing that has not been changed is the battery. Other than the Saturn install the wiring harness is unmolested as far as the charging system is concerned. All of my engine bay grounds are good, clean, and tight. My battery connections are clean and tight, I wired up the alternator correctly.

And to add insult to injury I blew the small cooling hose that runs down from the water pipe near the alternator last night, but that didn't happen until I got home, therefore that is not the root of my problems but rather one more thing to fix.

Any help would be greatly appreciated, I'm thinking the battery may have a bad cell and is refusing the charge. If it's not that then I'm stumped because I've checked everything else I can think of. Before this started happening (no charging unless revs are up) the car would start around 14.1v and then gradually drop down to 13 and stay there, sometimes in as short as a 15 minute drive.

Also, the last remanufactured alternator would randomly cut out voltage while I was driving and would fluctuate (play games with me, making me think it would work properly). There have been a couple times to where it did not charge and the car subsequently shut off in the middle of traffic and wouldn't turn right back over but would on the second try.

That's everything relevant to the problem that I can recall, again any help would be appreciated.

-Nick

EDIT: I'm load testing the battery soon. It has been suggested to me that there is likely a short or a sulfated plate.

First make sure the alt fuse is not blown.
Then test battery and alt: http://www.dsmtuners.com/forums/new...reeway-electrical-problems.html#post151165661.
Then look for shorts: http://www.dsmtuners.com/forums/art...-partial-short-battery-drain.html#post1496998.

I wouldn't think that I could've gotten 14.5v on thr first startup after the alternator install if the fuse was blown. Alternator passes at the post. Will read the link about shorts.

It was the battery. Only a year and a half old but couldn't even crank the car today.

Many months and the issue has not been resolved. Have changed the CAS, 3 MPI relays, tried a friend's ecu (known to be good). I cleaned up all the grounds coming from the battery, cleaned the posts and replaced the terminals. Car ran fine for three days but the problem came back worse than ever today. I barely made it to work, it shut off 5 times in less than 10mi, I had to coast into my parking space. Power and ground wires are soldered and butt connectors removed on ecu wiring, battery is from April '14, alternator is a motorcity reman 160a single-wire unit, power wire to battery is #4 welding cable with a 200a inline fuse, and alt belt is only a couple months old and on tight.

I'm at a loss and have no idea. Wiring on this car appears to be in good shape. Symptoms are that I lose all power to the ecu, wideband goes into heater mode, and car shuts off with no warning.

Checked the ignition switch? Is there a turbo timer wired in?

Did you check (measure or light test) for shorts: http://www.dsmtuners.com/threads/finding-a-short-partial-short-or-battery-drain.179481/#post1496998. They could be draining your battery and/or bringing the voltage down.

There is no drain, I have 12.4-12.6 at the battery with the key on but not running, every time. Checking for shorts this weekend. There is no turbo timer, I am the turbo timer. Which ignition switch? The cylinder itself or the MPI? I have changed the MPI 3 times with no change. I have tested the grounds in the engine bay with a light and they all test good. Issue was even worse trying to make it home last night, I barely made it home. Car died while driving at 45mph and I managed to get it to kick back on in the time it took to slow down to about 25ish. A CEL popped on for a few seconds while it was running and tried to die and then disappeared. I tried to pull the code when I got home and there was nothing under the DTC tab in Link. I went to slow down to make the last turn on my way home and it died. I took 5min to get it restarted, I'm no longer driving it until I get this fixed because next time it may not restart.

Locals are suggesting a shorted wiring harness, the power transistor, and/or the coil pack.

Reman alts sold at auto stores are notorious for having problems, they are so badly refurbished - just search this forum and it will make you sick. Many people have to exchange them 3-4 times to get one that works (especially from A.Z.). I suggest you completely disconnect the alt (every wire - careful with the main large cable to not touch anything and tape it up), charge up the battery, and in daylight with minimal accessories on drive the car and see if problem is still there.

I went through five of those before getting the alt I have now, a motorcity reman cs130 single-wire rewound for 160a output. I get 14.5v at the post and 14.3-4v at the battery post, belt is on very tight and not slipping. Problem exists even when only running on battery power, tried that a few months back.

The electrical ignition switch connected to the lock cylinder in the steering column.
It's just something else to check, if it was failing it can cause many issues.
I'm looking at you saying it dies then will eventually crank & restart.
Just so we're clear it dies out, you keep turning it over & eventually restarts?

I went through an absolute ton of alternators. I finally settled on an ultra non-reman Saturn sc2, 4 wire harness, 96 amp and rewired everything positive (less individual sensors). I spent 2 years dealing with alternates that worked fine till they got hot or killed voltage regulators or physically came apart. Not a single problem since I went with that specific one. Solid 13.9-14.3 volts at all times.

wrencher said:

The electrical ignition switch connected to the lock cylinder in the steering column.
It's just something else to check, if it was failing it can cause many issues.
I'm looking at you saying it dies then will eventually crank & restart.
Just so we're clear it dies out, you keep turning it over & eventually restarts?

Click to expand...

Correct, though it used to restart the first time, every time. I'll check it tomorrow, I'm going to kick my own ass if that is the issue or there is a loose connection there.

jakelandry said:

I went through an absolute ton of alternators. I finally settled on an ultra non-reman Saturn sc2, 4 wire harness, 96 amp and rewired everything positive (less individual sensors). I spent 2 years dealing with alternates that worked fine till they got hot or killed voltage regulators or physically came apart. Not a single problem since I went with that specific one. Solid 13.9-14.3 volts at all times.

Click to expand...

I'm using a rewound 160amp Saturn-style (cs130) alternator that has a self-exciting alternator, is configured for single-wire setup. If I drop below 14v, there is a problem. I have had this alternator for three months and the problem only occurs a few days a month no matter what alternator I run (OEM, Saturn, GM).

The only thing that an hinder an alternators output is a bad circuit or a bad alternator. Since you are confident it's not your alternator you know for a fact it's a circuit somewhere. Check things that have been moved or live things such as the cool pack posts. I recently had my alternator positive post weld itself to my wastegate. It had plenty of clearance until thermal expansion combined with engine movement made the 2 connect. Due to the fact that you're not popping fuses shorts will be hard to find. Pull some logs of the 3 scenarios if you can.

wrencher said:

The electrical ignition switch connected to the lock cylinder in the steering column.
It's just something else to check, if it was failing it can cause many issues.
I'm looking at you saying it dies then will eventually crank & restart.
Just so we're clear it dies out, you keep turning it over & eventually restarts?

Click to expand...

Just checked a log with the "KeyOn" and "KeyStart" values displayed, the KeyOn value remains on even through the voltage drops.

jakelandry said:

The only thing that an hinder an alternators output is a bad circuit or a bad alternator. Since you are confident it's not your alternator you know for a fact it's a circuit somewhere. Check things that have been moved or live things such as the cool pack posts. I recently had my alternator positive post weld itself to my wastegate. It had plenty of clearance until thermal expansion combined with engine movement made the 2 connect. Due to the fact that you're not popping fuses shorts will be hard to find. Pull some logs of the 3 scenarios if you can.

Click to expand...

Yeah, the two are not welded together. Logs attached. The second log has a big drop at 274.262 seconds, recovers, and ends up shutting itself off at the end, that was not me.[DOUBLEPOST=1411411675][/DOUBLEPOST]More recent logs are here in attachments.

Swapped PTU and tried another coil yesterday, no luck. Car died four times within 3/4 of a mile. Parked and towed it. In the process of changing the wiring harness now.

Its been a while. Any update on this?

Replaced the entire Engine/ECU wiring harness a couple weeks ago. Found that one of the retaining clips in the ECU plug had broken and one of the power wires could disconnect itself at will, of course I found that after swapping the harness. I'm sure there were other problems.

Voltage is stable (so far), currently dealing with injector and coolant temp sensor issues (I suspect the plug). Deadtime on PTE 1000s obviously isn't 450 like the Link wiki says, I have small misfires at idle. And The connection to my coolant temp sensor is off because the temperature oscillated by as much as 20 degrees while cruising but would stay steady at a normal 203 while idling. Jiggled the connector and it stabilized, going to mess with it tomorrow, not sure how I would tighten the plug's connection.

Log of coolant temp sensor idiocy, starts getting erratic around 244 seconds into the log:

There should be a couple ways to tighten that plugs connection. You can use needlenose pliers to very carefully squeeze the terminal in the connector so it is a little flatter. That might make it hold to the sensor better. It will be a little tougher to slip onto the sensor though.

Thinking about it though, jiggling it could also mean that the problem is a break in the wire, right at the connector. That would just mean either resoldering or replacing the terminal.

Do you still have the original ECT connector? Many people have had them break over the years and they usually get repaired with just a 250 faston terminal(no plug), or a plug that is sort of close.

I managed to get my hands on a factory connector a couple months ago with good connections at the plug. Thought about sticking an eyeglass screwdriver in and bending the contacts tighter. Running errands and should have time to tinker later.

Keep us updated on your injector issue please. I'm having the same problem.

I 'm just curious on when shoving a much higher amp alternator on stock wiring that is designed for 70amp draw, aren't we a bit afraid of engine fires due to the lesser gauge wiring now being massive resistors when that high amp draw commences heating up that wire like a glow coil of sorts?

One would think that a total rewire with larger gauge wire would reduce this resistance factor ..

DSM1G90 said:

I 'm just curious on when shoving a much higher amp alternator on stock wiring that is designed for 70amp draw, aren't we a bit afraid of engine fires due to the lesser gauge wiring now being massive resistors when that high amp draw commences heating up that wire like a glow coil of sorts?

One would think that a total rewire with larger gauge wire would reduce this resistance factor ..

Click to expand...

I'm running the equivalent of 4ga with a 200a inline fuse from the alt post to the battery post and haven't had any issues with fires or any other nonsense of that nature yet.

smills1840 said:

Keep us updated on your injector issue please. I'm having the same problem.

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I've seen deadtimes for these injectors as low as 315ms, I'll mess with my settings throughout the week. My gut is telling me it'll be somewhere between the 330-350ms range.

I've got fic 950s and I have a rough idle as well. Let me know if your latency changes help

with fires or any other nonsense of that nature yet.

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Don't rule the term of nonsense just yet, for it's not fun when you do get a fire caused by any means, for been there and done that with sudden fires of an unknown reason.

Seen a few DSM's in yards halfway burned up due to engine fires.